1. Field of the Invention (Technical Field)
Instrument comprising a cable or tube provided with a propulsion device
The invention relates to an instrument comprising a cable or tube, and a propulsion device for moving the cable or tube in a hollow space. Such an instrument may be used for moving in industrial tubular constructions such as pipes, tubes or sewer systems. However, such an instrument is also useful in medical applications when the hollow space is formed by esophagus, stomach, small intestine or blood vessels. Others to be mentioned are the bladder, windpipe, large intestine, duodenum, auditory duct and nose. Other possible spaces are the abdominal cavity, chest cavity, nasal and sinus cavities, the epidural cavity, hollow bones, etc.
Hereinafter the instrument of the invention will be further elucidated by way of its use as colonoscope. It is explicitly remarked, however, that the invention is not limited to just such a medical instrument but that all possible instruments as indicated above fall within the scope of the invention.
Patients suffering from intestinal complaints are usually subjected to a colonoscopy. With this examination, the patient is first given a laxative liquid to drink, after which the large intestine evacuates. Then a 1.5 meter long thin tube is introduced. On the tip of the known colonoscope used for this purpose a camera is provided with a light source and a duct through which an instrument can be introduced into the intestine. In view of the possibility of complications arising during anesthesia, a colonoscopy is in principle performed while the patient is conscious.
A drawback of the colonoscope is that the tip is introduced from a distance, via a long thin tube. There is a possibility that the tip catches behind projections in the intestinal wall so that pushing forces develop that cause the tube to buckle. When the tube buckles, considerable forces are exerted on the intestinal wall, causing cramp and pain. In the worst case the intestinal wall may become perforated, which may lead to life-threatening situations.
2. Description of Related Art
The prior art discloses various alternative solutions to reduce the problems with moving the colonoscope in the large intestine of the patient. Examples are sliding systems that work with balloons as shown in U.S. Pat. No. 3,895,637; U.S. Pat. No. 4,676,228; U.S. Pat. No. 4,690,131; U.S. Pat. No. 5,337,732; U.S. Pat. No. 5,398,670; and U.S. Pat. No. 5,454,364. Other known systems are embodied with suction cups, see for example U.S. Pat. No. 5,906,591 and U.S. Pat. No. 6,309,346 BI; with wheels, see U.S. Pat. No. 6,648,814 B2, or with belts extending over the length of the colonoscope, see U.S. Pat. No. 6,695,771; U.S. Pat. No. 5,562,601; U.S. Pat. No. 6,071,234; and U.S. Pat. No. 6,224,544.